Cell extracts of Streptomyces antibioticus, an oleandomycin producer, can inactivate oleandomycin in the presence of UDP-glucose. The inactivation can be detected through the loss of biological activity or by alteration in the chromatographic mobility of the antibiotic. This enzyme activity also inactivates other macrolides (rosaramicin, methymycin, and lankamycin) which contain a free 2'-OH group in a monosaccharide linked to the lactone ring (with the exception of erythromycin), but not those which contain a disaccharide (tylosin, spiramycin, carbomycin, josamycin, niddamycin, and relomycin). Interestingly, the culture supernatant contains another enzyme activity capable of reactivating the glycosylated oleandomycin and regenerating the biological activity through the release of a glucose molecule. It is proposed that these two enzyme activities could be an integral part of the oleandomycin biosynthetic pathway.

The relatively warm climate conditions prevailing today in the Mediterranean region limit cold geomorphological processes only to the highest mountain environments. However, climate variability during the Late Pleistocene and Holocene has led to significant spatio-temporal variations of the glacial and periglacial domain in these mountains, including permafrost conditions. Here, we examine the distribution and evolution of permafrost in the Mediterranean region considering five time periods: Last Glaciation, deglaciation, Holocene, Little Ice Age (LIA) and present-day. The distribution of inactive permafrost-derived features as well as sedimentary records indicates that the elevation limit of permafrost during the Last Glaciation was between 1000 m and even 2000 m lower than present. Permafrost was also widespread in non-glaciated slopes above the snowline forming rock glaciers and block streams, as well as meter-sized stone circles in relatively flat summit areas. As in most of the Northern Hemisphere, the onset of deglaciation in the Mediterranean region started around 19-20 ka. The ice-free terrain left by retreating glaciers was subject to paraglacial activity and intense periglacial processes under permafrost conditions. Many rock glaciers, protalus lobes and block streams formed in these recently deglaciated environments, though most of them became gradually inactive as temperatures kept rising, especially those at lower altitudes. Following the Younger Dryas glacial advance, the Early Holocene saw the last massive deglaciation in Mediterranean mountains accompanied by a progressive shift of permafrost conditions to higher elevations. It is unlikely that air temperatures recorded in Mediterranean mountains during the Holocene favoured the existence of widespread permafrost regimes, with the only exception of the highest massifs exceeding 2500-3000 m. LIA colder climate promoted a minor glacial advance and the spatial expansion of permafrost, with the development of new protalus lobes and rock glaciers in the highest massifs. Finally, post-LIA warming has led to glacial retreat/disappearance, enhanced paraglacial activity, shift of periglacial processes to higher elevations, degradation of alpine permafrost along with geoecological changes.

In COPD patients the burden of emphysema on CT scan and DLCO predict a clinically meaningful decline in exercise capacity.

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A B S T R A C TNatural conditions that explain the triggering of snow avalanches are becoming better-known, but our understanding of how socio-environmental changes can influence the occurrence of damaging avalanches is still limited. This study analyses the evolution of snow avalanche damage in the Asturian Massif (NW Spain) between 1800 and 2015, paying special attention to changes in land-use and land-cover patterns. A damage index has been performed using historical sources, photointerpretation and fieldwork-based data, which were introduced in a GIS and processed by means of statistical analysis. Mapping allowed connecting spatiotemporal variations of damage and changes in human-environment interactions. The total number of victims was 342 (192 dead and 150 injured). Results show stability in the number of avalanches during the study period, but a progressive decrease in the damage per avalanche. Changes in land use explain the evolution of damage and its spatial/temporal behaviour. The role played by vegetation cover is at the root of this process: damage was the highest during the late 19th and early 20th centuries, when a massive deforestation process affected the protective forest. This deforestation was the result of demographic growth and intensive grazing, disentailment laws and emerging coal mining. Since the mid-20th century, the transformation of a traditional landmanagement system based on overexploitation into a system based on land marginalization and reforestation, together with the decline of deforestation due to industrial and legal causes, resulted in the decrease of avalanches that affected settlements (mostly those released below the potential timberline). The decrease of damage has been sharper in the western sector of the Asturian Massif, where oak deforestation was very intense in the past and where lithology allows for a more successful ecological succession at present. Taking into account that reforestation can be observed in mountain environments of developed countries worldwide, and considering present initiatives conducted to counteract its negative cultural effects by means of grazing and clearing operations, planning is imperative, and this research provides useful information for environmental management policies and risk mitigation in avalanche prone areas.